DENTON -- A Caroline County jury yesterday found Michael Whittlesey guilty on two counts of first-degree murder in the 1982 killing of his friend Jamie Griffin, a 17-year-old Baltimore County youth whose whereabouts was a mystery until his buried remains were discovered in 1990 in Gunpowder Falls State Park.

The jury of seven men and five women deliberated just 2 1/2 hours -- less time than lawyers spent in their closing arguments.

Whittlesey, now 29, stood quietly but frowned as the jury's forewoman announced that he had been found guilty of premeditated murder and felony murder.

During sentencing arguments scheduled to begin here April 12, Baltimore County prosecutors will ask that Whittlesey be given the death penalty.

Reaction among courtroom spectators was reserved, even though Jamie's parents, Norville and Lou Ellen Griffin, and other family members and friends were present when the jury announced its verdict. Mr. and Mrs. Griffin, who never gave up their personal search for their son until his remains were found, declined to comment, and jurors were ordered not to discuss the case.

Baltimore County Assistant State's Attorney Mickey J. Norman said he hoped the verdict would bring some consolation to the Griffin family. "I think the thing I'm happiest about is that the Griffins got to have some relief that Jamie's killer has been found guilty," he said.

A critical test of the capital case against Whittlesey during nine days of often-confusing testimony was the prosecution's ability to convince the jury that the defendant had not only killed Jamie but also robbed the youth, even though he was not being tried on a formal robbery charge.

Because Whittlesey had been convicted of robbing Jamie in a 1984 trial, he could not be charged again with the same crime for this case. Nor could his 1982 conviction be mentioned in front of the jurors for fear of prejudicing them against the defendant.

Whittlesey never testified during his murder trial.

Whittlesey is currently serving a 25-year prison sentence for the robbery of Jamie's car keys and his money and for the theft of his car and other possessions. He was not charged with murder until Jamie's remains were recovered.

Public defenders argued that Jamie and Whittlesey were not the only two youths in the park the day Jamie died and hinted that someone other than the defendant was involved in the death.

In his closing argument, Mr. Norman suggested that Whittlesey lured Jamie into the park with a tall tale of buried treasure and then beat and stabbed his longtime friend to get money he believed the boy was carrying. Once Jamie had fallen and bled to death, Mr. Norman said, Whittlesey buried the body in a shallow grave, took Jamie's car and drove to Atlantic City, N.J., to gamble.

A medical expert for the prosecution testified earlier in the trial that Jamie's bones showed evidence of multiple stab wounds to the torso and blunt-force blows to the front and rear of the skull.

Baltimore County Assistant Public Defender Donald E. Zaremba argued that the "defects" or marks and fractures could have been caused by natural deterioration and by searchers who inadvertently damaged the remains while searching for them.

In a secret tape-recording police made of conversations between Whittlesey and a friend, David Strathy, Whittlesey said that Jamie had taken LSD in the park and run face-first into a tree. Whittlesey acknowledged that "I mighta pushed him," but insisted throughout most of the tapes that Jamie had hit the front of his head against a tree.